With the evolution of cloud computing, organizations are outsourcing the storage and rendering of volume (i.e., 3D data) to cloud servers. Data confidentiality at the third-party cloud provider, however, is one of the main challenges. Although state-of-the-art non-homomorphic encryption schemes can protect confidentiality by encrypting the volume, they do not allow rendering operations on the encrypted volumes. In this chapter, we address this challenge by proposing 3DCrypt-a modified Paillier cryptosystem scheme for multiuser settings that allows cloud datacenters to render the encrypted volume. The rendering technique we consider in this work is the pre-classification volume ray-casting. 3DCrypt is such that multiple users can render volumes without sharing any encryption keys. 3DCrypt's storage and computational overheads are approximately 66.3 MB and 27 s, respectively, when rendering is performed on a 256 × 256 × 256 volume for a 256 × 256 image space. We have also proved that 3DCrypt is INDistinguishable under Chosen Plaintext Attack (IND-CPA) secure.

Chapter Contents:

• Abstract
• 3.1 Introduction
• 3.2 Related work and background
• 3.2.1 Encrypted domain rendering
• 3.2.2 3D images
• 3.2.3 Volume ray-casting
• 3.3 System model
• 3.4 Proposed approach
• 3.5 Solution details
• 3.5.1 Data preparation
• 3.5.2 Ray-dependent rendering
• 3.5.3 Composition
• 3.6 Construction details
• 3.7 Security analysis
• 3.8 Implementation and experiment
• 3.9 Conclusions
• References

Inspec keywords: cloud computing; storage management; data privacy; image classification; cryptography; rendering (computer graphics)

Other keywords: 3DCrypt storage; cloud computing; indistinguishable-under-chosen plaintext attack; rendering technique; 3D images; IND-CPA; preclassification volume ray-casting; cloud datacenters; data confidentiality; cloud servers; third-party cloud provider; nonhomomorphic encryption schemes

Subjects: Computer vision and image processing techniques; Cryptography; Data security; Graphics techniques; File organisation; Internet software; Image recognition